Implement AsRef<Path> for Arc<PathBuf>

[vitiral]

Possibly also implement Borrow and Deref.

I would like to use Arc<PathBuf> to be the equivalent of PathBuf for traits in my library, path_abs.

However, I get errors like this:

751 | impl PathMut for Arc<PathBuf> {
    |      ^^^^^^^ the trait `std::convert::AsRef<std::path::Path>` is not implemented for `alloc::sync::Arc<std::path::PathBuf>`
    |
    = help: the following implementations were found:
              <alloc::sync::Arc<T> as std::convert::AsRef<T>>
    = note: required because of the requirements on the impl of `PathInfo` for `alloc::sync::Arc<std::path::PathBuf>`

[abonander]

You can also get Arc<Path> via .into() on &Path or PathBuf.

[vitiral]

Of course, but that doesn't let you generalize for trait bounds in a library.

[JanBeh]

To my understanding, adding new implementations of AsRef for smart pointers like Arc breaks type inference because of how some code currently uses .as_ref(). That said, I still think Arc<PathBuf> should implement AsRef<Path>. But it may be difficult to tackle.

Perhaps this issue could be closed and refer to #45742 for a (hopefully future) general solution of the problem.

[Enselic]

Triage: There were no objections to close as duplicate, so let's do that.

Duplicate of #45742